Richard Garsthagen, Technical Marketing Manager at VMware, published on his blog another very interesting insight about inner parts of the new ESX Server 3.0.
This time he talks about the new GuestSDK:
Since the release of VI3, VMware has also introduced a GuestSDK. What they have done is open up VMware Tools so your own applications can talk to it and request information about the real outside world, especially about resource consumption. The nice thing about using the GuestSDK is that you can get information fast and very frequent. VMware support querying the VMware Tools for information by at least 4 times a second without major overhead and I have found out in practice you can go much higher then that…
Read the whole article and download his sample program: VMPerfMon.